Dynamo-electric machine.



A. A. PIPER.

DYNAMO ELECTRIC MACHINE.

APPLICATION rum) OCT- 14, 1908.

' 1,072,647, Patented Sept. 9,1913.

2 sums- 11231: 1.

Z'&M; l v I COLUMB A PLANOORAPH 80 W UNITED STATES PATENT OFFICE.

ALVIN A. PIFER, 0F CLEVELAND, OHIO, ASSIGNOR TO CLEVELAND ARMA'IUREWORKS, 0F CLEVELAND, OHIO, A PARTNERSHIP COMPOSED OF ALVIN A. PIFER ANDJAMES L. MAULDIN.

DYNAMO-ELECTRIC MACHINE.

To all whom it may concern:

Be it known that I, ALVIN A. PIFER, a citizen of the United States,residing at Cleve land, in the county of Cuyahoga and State of Ohio,have invented a certain new and useful Improvement in Dynamo- ElectricMachines, of which the following is a full, clear, and exactdescription.

The present invention is directed to an improvement in dynamo electricmachines and especially concerns a form of variable speed motor of thetype invented by myself and C. E. F. Ahlm forming the subject of PatentNo. 900,420, October 6th, 1908, variable speed motor. This type of motorembodies pole pieces for the several field magnets, the pole piece foreach magnet being divided transversely,that is to say, parallel with theaxis of the armature, the two sec tions of the pole piece being movabletoward and from each other to vary the strength of the magnetic fieldand consequently the rate of the armature rotation.

I have discovered that by the improvement to be described below, theratio of variation may be considerably increased without complicatingthe structure or impairing the operation of the mechanism.

It has been my object to attain these results without departing from theessential principles of the machine disclosed in said patent, and itwill be seen that I have attained this object and other desirableadvantages by that embodiment of my invention described in the followingspecification with reference to the accompanying draw ings, in which;

Figure 1 is a side elevation of a variable speed motor constructed inaccordance with my invention, the operating rings being broken away inpart and the ole shoe sections being in their closed position. Fig. 2 isa side elevation, with the operating rings and double screw by whichthey are operated removed. Fig. 3 is an enlarged section through themotor, with the armature removed, showing the structure of the parts.Fig. 4 is an enlarged detail showing the connection of the operatingrings to the operating screw.

The type of machine herein shown is based upon the principle of havingpole shoes for the field magnets made in sections movable toward andfrom each other for the purpose of increasing or decreasing the numberof Specification of Letters Patent.

Application filed October 14, 1908.

Patented Sept. 9,1913.

Serial No. 457,656.

lines of force passing through the armature and thereby varying thespeed of the latter.

. at the same time they are moved toward and from each other. Theincrease and decrease in air gap between the armature and the pole shoesections occasioned by this movement rapidly decreases or increases thenumber of lines of force passing into the armature.

In the design of machine which I have here shown I provide the inner endof the coresA of the field magnets with projecting flanges A havingslideways thereon which support and along which slide the sections B, Bof the pole shoe placed between each core and the armature C. It is notpractical to move the pole shoe sections if they come in actual contactwith the core, and consequently I space the said sections slightly apartfrom the end of the core and use strips of some suitable non-magneticmaterial, such as brass for engaging the slideways of the pole. Thesebrass strips B are secured to the pole shoe sections and suitably shapedto engage the said slideways and slide freely thereon. It will be seenthat these slideways are each parallel with the tangent to the armatureat the point out by the extended axis of the core, andtherefore anymovement of the pole shoe sections along said ways toward orfrom eachother will cause a corresponding travel toward or from the surface ofthe armature and thus rapidly increase or diminish the resistance givenby the air gap between the pole shoe and the armature and increasing ordiminishing correspondingly the number of lines of force s unted awayfrom the armature.

The means by which the several sections are caused to travelsimultaneously in their proper direction comprises a pair of rings 1), Dconcentric with the armature on each end of the motor. The set of ringsat one end receive their motion directly from an operating shaft, whilethe set at the other end serve as equalizers. Considering the rings onthe end connected with the operating shaft, it will be seen that onering, namely, the outer D, has a number of pins D projecting therefrominto vertical slots of the left hand member of each pair of thesectional pole shoes, mine the inner ring has a number of-pins Dprojecting into vertical slots of the right hand members of thesectional pole shoes.

It will be obvious that a movement of the inner ring' in one directionand a movement of the outer ring in the opposite direction will cause acorresponding movement of the same extent for each section of all of thepole shoes. I prefer to attain this movement by means of a shaft Dmounted on the frame of the machine and having two reversed threads D, Dat the end thereof, one of said threads D engaging a swiveled nut Dfixed to the inner ring and the other thread D having a pitch thereverse of the first thread engaging a swiveled nut D on the outer ring.The reason'fo-r swiveling these'nuts is to avoid any strain due to themovement of the nuts in a circular direction of the armature when thesections are moved away from each other.

It will be seen that by means of the construction described I have madeit possible to move the pole shoe sections away from the face of thearmature at the same time they are moved away from each other and thusattain the object sought, of increas ing the ratio of variation possiblewithin that radius described;

Having thus described claim:

7 1. In combination in a dynamo electric machine having an armature anda plurality of sets of field poles, a regulator comprisinga pair of poleshoe sections at the inner endot each pole, each of the poles havingguideways which support the shoes independently or the shoes on, theother.

my invention, I

poles, and permit movement of the shoes toward or away from each otherand at the same time toward or from the armature and means operativelyconnected to the shoes for simultaneously shitting all the shoes.

2. In combination in a dynamo electric machine, an armature, a fieldmember having a plurality of poles a pair of pole shoe sectionssupported by each pole and having a sliding connection therewith formovement toward and away from each other along the line parallel withthe tangent to the armature at the point out by the ex tended axis ofthe core, and means for simultaneously shifting the pole shoe sectionscomprising one shifting means having operative connections withalternating sections, and another shitting means having operativeconnections with the remaining alternating sections.

3. In a dynamo electric machine, an armature a field member having aplurality of inwardly projecting poles, each supporting at its inner enda pair otpole shoe sections havingsliding connections with the pole sothat they may be moved toward or away from each other along a lineparallel to the line tangent to the armature at the intersection of thearmature and 'pole aids, and means for shifting the pole shoe sectionsof the different poles toward oraway from each other comprising a pairof shifter members each loosely connected with alternating sections.

4; In a dynamo electric machine, an armature; a field member having aplurality of inwardly projecting poles each supporting at its inner enda pair of pole shoe sections,

said pole shoe sections having sliding con nections with the pole onopposite sides of therlatter so that they may be moved toward and awayfrom each other on a line parallel with a line tangent to the armatureat the intersection of the armature and pole aXis, and means forsimultaneously shifting the pole shoe sections of the different 'polestoward or away from each other comprising a pair of rings, each looselyconnected with alternating sections.

In testimony whereof, I hereunto afliX my signature in the presence oftwo witnesses.

ALVIN A. PIFER.

Witnesses: i

H. R. SULLIVAN,- J. M. \VooDwAnD.

Copies or this patent may be obtained for five cents each, by addressingthe Gorn'missioner of Iiatents. Washington, I). C.

